Arborist exam practice test

20 questions · 10 domains · about 20 minutes. Pick an answer to see whether you’re right and why.

1. Question 1 of 20 · Tree BiologyRay cells in wood run in which direction relative to the grain?

   A.Perpendicular to the grain (radially)B.Parallel to the grain (longitudinally)C.Tangentially around the annual ringsD.Diagonally through the wood
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   Answer: A. Perpendicular to the grain (radially)

   Wood rays radiate outward from the pith like spokes of a wheel; their radial orientation allows them to move photosynthates and water laterally across the wood, connecting the phloem (inner bark) with the interior parenchyma for nutrient exchange and storage.

2. Question 2 of 20 · Tree BiologyTranspiration pull (tension) in the xylem is generated by:

   A.Active pumping by companion cells in the phloemB.Root pressure pushing water upward from belowC.Osmosis occurring in the phloemD.Evaporation of water from leaf mesophyll cells creating negative pressure in the xylem
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   Answer: D. Evaporation of water from leaf mesophyll cells creating negative pressure in the xylem

   As water evaporates from mesophyll cell walls into air spaces and out through stomata, the resulting water deficit creates negative pressure (tension) that is transmitted through the continuous water column to pull more water upward from the roots.

3. Question 3 of 20 · Tree Identification and SelectionThe term 'included bark' refers to:

   A.A graft union where the scion has grown into the rootstockB.Bark tissue encased inside a branch union, reducing the strength of the attachmentC.Exterior bark that is rough and deeply furrowedD.Bark that has grown over a wound creating a solid callus
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   Answer: B. Bark tissue encased inside a branch union, reducing the strength of the attachment

   Included bark forms when two stems or a branch and trunk meet at a narrow, V-shaped angle, forcing bark inward; the embedded bark creates a plane of weakness with no interlocking wood fibers, making such unions prone to splitting under stress — a major tree hazard.

4. Question 4 of 20 · Tree Identification and SelectionWhich statement about the USDA Hardiness Zone map is correct?

   A.Each zone represents a 10°F difference in average annual extreme minimum temperatureB.Each zone is based on average annual precipitationC.Each zone is based on average summer maximum temperatureD.Each zone represents a 5°F difference in average annual extreme minimum temperature
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   Answer: A. Each zone represents a 10°F difference in average annual extreme minimum temperature

   The USDA map divides North America into 13 zones, each spanning a 10°F range in average annual extreme minimum temperature (with a and b half-zones each representing 5°F); this single variable determines whether a plant can survive winter cold, though supplemental heat zone maps address summer heat tolerance.

5. Question 5 of 20 · Soil ManagementWhich of the following fertilizer labels correctly identifies the N-P-K ratio?

   A.12-4-8 means pH 12, 4% organic matter, 8% clayB.12-4-8 means 12% slow release, 4% fast release, 8% trace elementsC.12-4-8 means 12% N, 4% P2O5, 8% K2OD.12-4-8 means 12 lb N, 4 lb P, 8 lb K per bag
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   Answer: C. 12-4-8 means 12% N, 4% P2O5, 8% K2O

   By regulatory convention, fertilizer labels express nitrogen as elemental N (%), phosphorus as P₂O₅ (%), and potassium as K₂O (%) by weight of the product; this is important to understand when calculating actual elemental rates applied.

6. Question 6 of 20 · Installation and EstablishmentWhat is the primary advantage of bare root planting?

   A.It results in faster establishment than container stockB.It is less expensive and allows for inspection and correction of root defectsC.It can be used year-round in all climatesD.The root system is fully intact and undisturbed
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   Answer: B. It is less expensive and allows for inspection and correction of root defects

   With no soil obscuring the roots, the arborist can visually inspect and correct circling, damaged, or malformed roots before installation, reducing long-term structural problems at lower cost.

7. Question 7 of 20 · Installation and EstablishmentCompared to container or B&B stock, bare root trees are best planted during:

   A.Any time of year as long as supplemental irrigation is providedB.Early fall, just after leaves have droppedC.Summer, when soil temperatures are highestD.The dormant season, before buds break in spring
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   Answer: D. The dormant season, before buds break in spring

   Bare root trees have no soil protecting their roots from drying; planting in full dormancy minimizes water demand and transpiration stress while cool, moist soil conditions support rapid root regeneration.

8. Question 8 of 20 · PruningWhich of the following is a potential consequence of removing more than 25% of a tree's live crown in one season?

   A.A significant reduction in the tree's susceptibility to storm damageB.Severe stress, reduction in food storage, and increased risk of decline or deathC.Permanent suppression of epicormic bud activityD.Excessive crown density in the following growing season
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   Answer: B. Severe stress, reduction in food storage, and increased risk of decline or death

   The live crown is the tree's solar panel; removing more than one-quarter of it in a single season depletes carbohydrate reserves faster than they can be replenished, compromising growth, defense, and wound closure simultaneously.

9. Question 9 of 20 · PruningPollarding is best described as:

   A.Selectively thinning the crown to reduce wind resistanceB.Removing all lateral branches while preserving the central leaderC.Removing the entire crown of a tree to near ground level repeatedlyD.A training system where a tree is repeatedly cut back to the same set of cut points to maintain a specific size
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   Answer: D. A training system where a tree is repeatedly cut back to the same set of cut points to maintain a specific size

   Pollarding is a legitimate and ancient management system that works because it is established on young trees with small cuts and maintained on a consistent cycle, allowing the characteristic 'knuckle' of callus to develop at each cut point.

10. Question 10 of 20 · PruningWhat is the branch bark ridge?

    A.The area of smooth bark where the branch collar endsB.A strip of bark on the underside of a branch union indicating a weak attachmentC.A ridge of raised bark in the upper angle of a branch union where the branch and stem tissue interlockD.The point at which bark is removed to expose the wound before pruning
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    Answer: C. A ridge of raised bark in the upper angle of a branch union where the branch and stem tissue interlock

    The branch bark ridge is a visible, raised seam of bark at the top of a branch union; it marks the boundary between stem and branch tissue and serves as one of the two landmarks used to position a proper pruning cut.

11. Question 11 of 20 · Diagnosis and TreatmentThe term 'PHC practitioner' refers to an arborist who takes which approach to managing tree and landscape health?

    A.One who takes a holistic, preventive approach — monitoring, diagnosing, and addressing the full range of biotic, abiotic, and cultural factors affecting plant healthB.One who focuses primarily on soil chemistry and fertility management to optimize tree nutritionC.One who is certified specifically in plant pathology by a state university extension programD.One who specializes exclusively in pesticide applications for high-value trees
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    Answer: A. One who takes a holistic, preventive approach — monitoring, diagnosing, and addressing the full range of biotic, abiotic, and cultural factors affecting plant health

    A PHC practitioner applies an integrated, ecosystem-based perspective that addresses the whole tree in its whole environment — monitoring proactively, diagnosing accurately, and selecting the least-invasive interventions across cultural, biological, and chemical tactics to sustain long-term landscape health.

12. Question 12 of 20 · Diagnosis and TreatmentWhite rot fungi decompose which wood components?

    A.Lignin and cellulose, leaving bleached, spongy woodB.Lignin only, leaving cellulose intactC.Heartwood resin canals exclusivelyD.Cellulose only
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    Answer: A. Lignin and cellulose, leaving bleached, spongy wood

    White rot fungi produce ligninolytic enzymes that break down both lignin and cellulose, leaving the wood with a pale, bleached, spongy or stringy texture; because lignin is removed, white rot-decayed wood is structurally weaker than it may initially appear.

13. Question 13 of 20 · Trees and ConstructionSuspended pavement systems differ from conventional paving in that they:

    A.Use lighter paving materials that exert less force on roots beneathB.Incorporate permeable aggregate base layers that roots can penetrateC.Span structural supports (soil cells) that carry pavement loads, leaving soil below uncompacted and available for root growthD.Allow roots to grow directly through expansion joints in the pavement
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    Answer: C. Span structural supports (soil cells) that carry pavement loads, leaving soil below uncompacted and available for root growth

    In suspended pavement systems, a structural framework transfers all surface loads to footings, keeping the enclosed soil volume completely free of compaction — unlike conventional paving, where the compacted aggregate base and subbase destroy rooting volume.

14. Question 14 of 20 · Trees and ConstructionRaising the grade around a tree (adding soil fill) causes harm primarily because:

    A.It buries the root flare, reduces soil oxygen for roots, and increases bark moisture, leading to root death and decayB.It adds weight that compresses the soil and breaks surface rootsC.It changes the pH of the soil immediately around the trunkD.It prevents mycorrhizal fungi from completing their life cycle
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    Answer: A. It buries the root flare, reduces soil oxygen for roots, and increases bark moisture, leading to root death and decay

    Burying the root flare with fill soil cuts off oxygen supply to roots and keeps the bark zone chronically moist, creating anaerobic conditions that cause root death and create entry points for wood-decay and Phytophthora pathogens.

15. Question 15 of 20 · Tree RiskThe term 'sail effect' in tree risk assessment refers to:

    A.The tendency of roots to fail on the leeward side during windstormsB.The visual assessment of branch attachment anglesC.A technique for measuring the height of a fallen treeD.The way a tree's crown intercepts wind, creating drag forces on the stem and root system
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    Answer: D. The way a tree's crown intercepts wind, creating drag forces on the stem and root system

    The crown acts like a sail, intercepting wind and converting it into bending and torsional forces transmitted down the stem to the root system; larger, denser crowns generate greater sail area and higher wind loads.

16. Question 16 of 20 · Tree RiskCrown dieback in a mature tree is considered a risk indicator primarily because it suggests:

    A.The tree has been recently transplantedB.Pest activity limited to the outer canopyC.Structural decline, decay, or root system problems that may compromise stabilityD.The tree is experiencing normal seasonal dormancy
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    Answer: C. Structural decline, decay, or root system problems that may compromise stability

    Crown dieback in an established tree typically reflects systemic stress such as root damage, vascular disease, or decay reducing water and nutrient flow; these same conditions often weaken structural integrity.

17. Question 17 of 20 · Safe Work PracticesWhich of the following is the correct action when a chainsaw chain brake activates during normal cutting?

    A.Disengage the brake while the saw is still runningB.Immediately restart the saw and continue cuttingC.Release the chain brake, assess why it activated, and correct the hazard before continuingD.Replace the chain before restarting the saw
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    Answer: C. Release the chain brake, assess why it activated, and correct the hazard before continuing

    Chain brake activation indicates a kickback event or inadvertent contact with the hand guard; the cause must be identified and corrected before resuming work to prevent a recurrence that could injure the operator.

18. Question 18 of 20 · Safe Work PracticesWhich of the following is the correct body position when bucking (cross-cutting) a log on the ground?

    A.Straddle the log with the bar between the legs for stabilityB.Stand to the side and slightly behind the cut, with the bar clear of your body lineC.Stand directly in front of the cut with your legs bracedD.Kneel directly behind the cut for maximum control
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    Answer: B. Stand to the side and slightly behind the cut, with the bar clear of your body line

    Standing to the side keeps the operator out of the plane of the bar in case of kickback or log roll; straddling or standing in front places the legs and torso directly in the path of the bar if control is lost.

19. Question 19 of 20 · Safe Work PracticesA high-visibility safety vest is required for arborists working on or near roadways under which standard?

    A.OSHA 1926.502B.ANSI/ISEA 107 and MUTCD requirements for worker visibilityC.ANSI Z133D.29 CFR 1910.132
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    Answer: B. ANSI/ISEA 107 and MUTCD requirements for worker visibility

    ANSI/ISEA 107 classifies high-visibility garments by background material, retroreflective tape, and design performance, while the MUTCD specifies which class is required based on the road type and vehicle speed.

20. Question 20 of 20 · Urban ForestryA diverse urban forest follows the '10-20-30 rule,' which recommends no more than:

    A.10% trees per block, 20% per neighborhood, 30% per districtB.10% conifer species, 20% broadleaf species, 30% shrub layer speciesC.10% invasive species, 20% exotic species, 30% native speciesD.10% of any one species, 20% of any one genus, 30% of any one family
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    Answer: D. 10% of any one species, 20% of any one genus, 30% of any one family

    The 10-20-30 rule, developed to prevent catastrophic losses like those caused by Dutch elm disease and emerald ash borer, sets diversity thresholds at the species, genus, and family levels to limit exposure to any single pest or pathogen.